Axial-flow fan

ABSTRACT

An axial-flow fan includes a hub and a plurality of blades integrally resin-molded to the hub at a plurality of joints, The plurality of blades are formed so as to project from an outer perimeter edge of the hub. Each joint has at least one first blade thinned-out part formed so that at least one radial rib extending radially toward an outer perimeter side is formed.

TECHNICAL FIELD

The present invention relates to an axial-flow fan, and relates inparticular to an axial-flow fan with which a hub and a plurality ofblades are integrally resin-molded, the blades being formed so as toproject from an outer perimeter edge of the hub.

BACKGROUND ART

An axial-flow fan with which a hub and a plurality of blades areintegrally resin-molded, the blades being formed so as to project froman outer perimeter edge of the hub has hitherto been used in an outdoorunit, or the like, of an air conditioning apparatus.

One such axial-flow fan has a thinned-out part formed in a joint of theblade with the hub, as illustrated in patent document 1 (JapaneseUnexamined Patent Application Publication No. 2011-74817).

SUMMARY OF THE INVENTION

However, formation of the thinned-out part in the joint of the bladeleads to narrowing of a space in which the resin injected into the moldflows toward the outer perimeter side during molding of the axial-flowfan. Therefore, in the axial-flow fan having the thinned-out part formedin the joint of the blade, the resin does not readily flow into aportion further toward the outer perimeter side from the thinned-outpart during molding, and there is a possibility that molding failuremight occur in the outer perimeter portion of the blade.

An object of the present invention is to form a thinned-out part in ajoint of a blade while minimizing molding failure in an outer perimeterportion of the blade in an axial-flow fan with which a hub and aplurality of blades are integrally resin-molded.

An axial-flow fan according to a first aspect is integrally resin-moldedwith a hub and a plurality of blades formed so as to project from anouter perimeter edge of the hub. A first blade thinned-out part isformed in a joint of the blade with the hub so that a radial ribextending radially toward the outer perimeter side is left.

The present inventors studied the shape of a rib left when forming athinned-out part on a joint of a blade, considering an inflow of resinduring molding to a portion further toward an outer perimeter side fromthe thinned-out part when forming the thinned-out part. As a result, thepresent inventors discovered that a first blade thinned-out part isformed so that a radial rib extending radially toward the outerperimeter side is left as mentioned above.

Such radial rib accelerates the flow toward the outer perimeter side ofresin injected in the mold during molding, and therefore allows afavorable inflow of resin to the portion further toward the outerperimeter side from the first blade thinned-out part during molding. Theradial rib also allows resin injected into the mold during molding toflow more easily toward the outer perimeter side, compared to the casewhen a rib not extending radially is left.

The thinned-out part can thereby be formed in the joint of the bladewhile minimizing molding failure in the outer perimeter portion of theblade in this axial-flow fan.

An axial-flow fan according to a second aspect is the axial-flow fanaccording to the first aspect, wherein a plurality of radial ribs aredisposed in a circumferential direction.

When a plurality of radial ribs are disposed in a circumferentialdirection as mentioned above, the portion where the resin flows to theportion further toward the outer perimeter side from the first bladethinned-out part can be increased in the circumferential directionduring molding.

The flow toward the outer perimeter side of resin injected into the moldduring molding can thereby be further accelerated in this axial-flowfan. The resin also can be allowed to flow in uniformly to any positionin the circumferential direction of the portion further toward the outerperimeter side from the first blade thinned-out part during molding.

An axial-flow fan according to a third aspect is the axial-flow fanaccording to the first or second aspect, wherein the radial rib extendson a straight line extending radially toward the outer perimeter sidefrom an axial center of the hub when viewing the hub and the blade froman axial direction.

When the radial rib is configured to extend on a straight line extendingradially toward the outer perimeter side from the axial center of thehub as mentioned above, the resin injected into the mold during moldingcan be controlled to flow directly toward the outer perimeter side.

The resin injected into the mold can thereby be allowed to flow moreeasily toward the outer perimeter side during molding in this axial-flowfan.

An axial-flow fan according to a fourth aspect is the axial-flow fanaccording to any of the first to third aspects, wherein a front edge ribcontinuing on a front edge of the blade is formed in the joint in aportion further toward the front edge side of the blade from the radialrib. A second blade thinned-out part larger than the first bladethinned-out part is formed between the front edge rib and the radial ribin the circumferential direction.

Forming the front edge rib continuing on the front edge of the blade ina portion further toward the front edge side of the blade from theradial rib in this axial-flow fan as mentioned above improves strengthat the front edge of the blade. However, when such front edge rib isformed, there is a possibility that the front edge rib and the vicinitythereof might be less likely to be cooled during molding.

Therefore, in this axial-flow fan, the front edge rib is formed and thesecond blade thinned-out part larger than the first blade thinned-outpart is formed between the front edge rib and the radial rib in thecircumferential direction, as mentioned above, so that a situation inwhich the front edge rib and the vicinity thereof are less likely to becooled during molding can be minimized.

The occurrence of sink, marks during molding can thereby be minimizeddespite the fact that the front edge rib is formed in addition to theradial rib in this axial-flow fan.

An axial-flow fan according to a fifth aspect is the axial-flow fanaccording to any of the second to fourth aspects, wherein the radialribs are equidistantly disposed in the circumferential direction.

When the radial ribs are equidistantly disposed in the circumferentialdirection as mentioned above, the resin easily flows in uniformly overthe plurality of radial ribs during molding.

The resin can thereby be allowed to easily flow in more uniformly in thecircumferential direction to the portion further toward the outerperimeter side from the first blade thinned-out part during molding inthis axial-flow fan.

An axial-flow fan according to a sixth aspect is the axial-flow fanaccording to any of the first to fifth aspects, wherein an indented partgoing in toward the front edge side of the blade is formed on a rearedge of the blade. The first blade thinned-out part is positionedfurther toward the front edge side of the blade from the indented partwhen viewing the hub and the blade from an axial direction.

Forming the indented part going in toward the front edge side of theblade on the rear edge of the blade in this axial-flow fan as mentionedabove designs for improvement of ventilating performance and/orsuppression of noise. However, when such indented part is formed, theresin does not readily flow in to the indented part and the vicinitythereof, and there is a possibility that molding failure in the indentedpart and the vicinity thereof may occur.

Therefore, in this axial-flow fan, the first blade thinned-out part ispositioned further toward the front edge side of the blade from theindented part as mentioned above, so that the resin flows in as far asthe indented part and the vicinity thereof without passing the firstblade thinned-out part during molding.

The inflow of resin to the indented part and the vicinity thereof isthereby ensured during molding and molding failure in the indented partand the vicinity thereof can be minimized, despite the fact that boththe first blade thinned-out part and the indented part are formed inthis axial-flow fan.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an outdoor unit in which is adoptedan outdoor fan as an axial-flow fan according to one embodiment of thepresent invention, in a condition having removed a ceiling platethereof.

FIG. 2 is a front view of the outdoor unit in which is adopted theoutdoor fan according to one embodiment of the present invention.

FIG. 3 is a perspective view of the outdoor fan according to oneembodiment of the present invention.

FIG. 4 is a plan view of a positive pressure face side of the outdoorfan according to one embodiment of the present invention.

FIG. 5 is a plan view of a negative pressure face side of the outdoorfan according to one embodiment of the present invention.

FIG. 6 is a side view of the outdoor fan according to one embodiment ofthe present invention.

FIG. 7 is an enlarged view of a joint of a blade and the vicinitythereof in FIG. 5.

FIG. 8 is a cross-sectional view along I-I in FIG. 7.

FIG. 9 is an enlarged view of a front edge rib and the vicinity thereofin FIG. 6.

FIG. 10 is a cross-sectional side view of a mold, for describing aprocess for molding the outdoor fan.

FIG. 11 is a cross-sectional view illustrating a portion of the mold forforming the joint of the blade and the vicinity thereof, for describingthe process for molding the outdoor fan.

DESCRIPTION OF EMBODIMENTS

An embodiment of the axial-flow fan according to the present inventionis described below based on the accompanying drawings. The specificconfiguration of the axial-flow fan according to the present inventionis not limited to the embodiment below, and modifications are possiblewithin a scope not deviating from the main point of the presentinvention. In the description below, an example in which the presentinvention is applied to an axial-flow fan configuring an outdoor unit isdescribed, but the present invention is not limited to this; it may beapplied to an axial-flow fan for another use.

(1) Overall Configuration of the Outdoor Unit

FIGS. 1 and 2 are drawings illustrating an outdoor unit 2 of an airconditioning apparatus in which is adopted an outdoor fan 70 as anaxial-flow fan according to one embodiment of the present invention.Here, FIG. 1 is a plan view of the outdoor unit 2 in a condition havingremoved a ceiling plate 57. FIG. 2 is a front view of the outdoor unit2. In the description below, words expressing directions and/or facesincluding “up,” “down,” “left,” and “right,” and/or “front face,” “sideface,” “back face,” “top face,” and “bottom face,” unless otherwisespecified, signify directions and/or faces in the case of regarding theoutdoor unit 2 illustrated in FIG, 2 as a front face.

The outdoor unit 2 has a structure (so called “trunk-type” structure),in which an internal space of a unit casing 51 is divided into left andright by a partitioning plate 58 extending in a vertical direction,whereby a blower compartment S1 and a machine compartment S2 are formed.The outdoor unit 2 is configured so that outside air is taken into theunit casing 51 from a back face and one part of a side face of the unitcasing 51 and the outside air is blown out from a front face of the unitcasing 51. The outdoor unit 2 mainly has the unit casing 51, refrigerantcircuit-configuring parts including a compressor 21, an outdoor heatexchanger 24, and refrigerant pipes connecting these machines, anoutdoor fan 70 (axial-flow fan), and a bell mouth 80. Here, an exampleis described, in which the blower compartment S1 is formed toward a leftside face of the unit casing 51 and the machine compartment S2 is formedtoward a right side face of the unit casing 51, but left and right maybe reversed.

The unit casing 51 is formed in a roughly rectangular parallelepipedform, and mainly houses the refrigerant circuit-configuring partsincluding the compressor 21, the outdoor heat exchanger 24, andrefrigerant pipes connecting these machines, and the outdoor fan 70. Theunit casing 51 has a floor plate 52, a blower compartment-side sideplate 53, a machine compartment-side side part 54, a blowercompartment-side front plate 55, a machine compartment-side front plate56, and a ceiling plate 57.

The floor plate 52 is a metal plate-form member configuring a bottomface of the unit casing 51. Two foundation legs 59 and 60 fixed to asite installation surface are provided beneath the floor plate 52.

The blower compartment-side side plate 53 is a metal plate-form memberconfiguring a side face portion toward the blower compartment S1 of theunit casing 51. A lower part of the blower compartment-side side plate53 is fixed to the floor plate 52. An intake port 53 a for outside airtaken into the unit casing 51 by the outdoor fan 70 is formed on theblower compartment-side side plate 53.

The machine compartment-side side plate 54 is a metal plate-form memberconfiguring one part of a side face portion toward the machinecompartment S2 of the unit casing 51 and a back face portion toward themachine compartment S2 of the unit casing 51. A lower part of themachine compartment-side side plate 54 is fixed to the floor plate 52.Here, the machine compartment-side side plate 54 covers a portion towardthe back face of the side face of the machine compartment S2. An intakeport 53 b for outside air taken into the unit casing 51 by the outdoorfan 70 is formed between an end part on the back face side of the blowercompartment-side side plate 53 and an end part on the blower compartmentS1 side of the machine compartment-side side plate 54.

The blower compartment-side front plate 55 is a metal plate-form memberconfiguring a front face portion of the blower compartment S1 of theunit casing 51 and one part of a front face portion of the machinecompartment S2 of the unit casing 51. A blow-out port 55 a for blowingout outside air taken into the unit casing 51 to the outside by theoutdoor fan 70 is provided on the blower compartment-side front plate55. A front side of the blow-out port 55 a is covered by a fan grill 55b. A lower part of the blower compartment-side front plate 55 is fixedto the floor plate 52, and an end part on the left side face sidethereof is fixed to an end part on the front face side of the blowercompartment-side side plate 53.

The machine compartment-side front plate 56 is a metal plate-form memberthat is removed during test running and/or maintenance in order toaccess the machine compartment S2 from the front face side of the unitcasing 51 and perform inspection, and the like, of the machines disposedinside the machine compartment S2. The machine compartment-side frontplate 56 is a metal plate-form member configuring one part of a frontface portion of the machine compartment S2 of the unit casing 51 and onepart of a side face portion of the machine compartment S2 of the unitcasing 51. An end part on the blower compartment S1 side of the machinecompartment-side front plate 56 is fixed to an end part on the machinecompartment S2 side of the blower compartment-side front plate 55, andan end part on a back face side thereof is fixed to an end part on thefront face side of the machine compartment-side side plate 54. Here, onepart of the front face portion of the machine compartment S2 of the unitcasing 51 is configured by the blower compartment-side front plate 55,but that part may be configured by the machine compartment-side frontplate 56. The blower compartment-side front plate 55 and the machinecompartment-side front plate 56 also may be an integrated member.

The ceiling plate 57 is a metal plate-form member configuring a top faceportion of the unit casing 51. The ceiling plate 57 is fixed to theblower compartment-side side plate 53, the machine compartment-side sideplate 54, and the blower compartment-side front plate 55.

The partitioning plate 58 is a metal plate-form member being disposed onthe floor plate 52 and extending in a vertical direction. Thepartitioning plate 58 divides the internal space of the unit casing 51into left and right to form the blower compartment S1 toward the leftside face and the machine compartment S2 toward the right side face. Thepartitioning plate 58 has a shape that is curved so that a centralportion in a front-to-back direction thereof projects toward the blowercompartment S1 side. A lower part of the partitioning plate 58 is fixedto the floor plate 52, an end part on a front face side thereof is fixedto the blower compartment-side front plate 55, and an end part on a backface side thereof is fixed to an end part on the machine compartment S2side of the outdoor heat exchanger 24.

The outdoor fan 70 is a propeller fan mainly with which a huh 71 and aplurality of (here, three) blades 72 are integrally resin-molded, theplurality of blades 72 being formed so as to project from an outerperimeter edge of the hub 71. The outdoor fan 70 is provided so as toface opposite the front face of the unit casing 51 inside the blowercompartment S1. More specifically, the outdoor fan 70 is provided so asto face opposite the blow-out port 55 a formed on the blowercompartment-side front plate 55 in a position on the front face side ofthe outdoor heat exchanger 24. Here, an indented part 72 a going intoward the front edge side of the blade 72 is formed on a rear edge ofthe blade 72, for the purpose of improvement of ventilating performanceand/or suppression of noise. The outdoor fan 70 is driven to rotate by afan motor 79 disposed between the outdoor fan 70 and the outdoor heatexchanger 24 in the front-to-back direction. The fan motor 79 issupported by a fan motor mount 61 extending in a vertical directionbetween the ceiling plate 57 and the floor plate 52. A detailedconfiguration of the outdoor fan is to be described.

The bell mouth 80 is a member having a bell-shaped opening 81 having anopen center, and is provided on the outer perimeter side of the outdoorfan 70. That is, the bell mouth 80 is provided so as to face oppositethe front face of the unit casing 51 in the same manner as the outdoorfan 70 inside the blower compartment S1, and the outer perimeter of theoutdoor fan 70 is surrounded by the opening 81. The bell mouth 80 isfixed to the front face of the unit casing 51. A portion of the bellmouth 80 toward the blower compartment-side side plate 53 is disposedproximally to a front-side end of the outdoor heat exchanger 24. Aportion of the bell mouth 80 toward the machine compartment S1 isdisposed proximally to the partitioning plate 58.

The outdoor heat exchanger 24 is a roughly L-shaped heat exchangerpanel, and is disposed on the floor plate 52 so as to follow the leftside face and the back face of the unit casing 51 inside the blowercompartment S1.

The compressor 21 is a sealed-type compressor having an uprightcylindrical shape, and is disposed inside the machine compartment S2.

Although not illustrated here, the machines, refrigerant pipes, and/orother refrigerant circuit-configuring parts in addition to thecompressor 21 also are disposed inside the machine compartment S2.

(2) Detailed Configuration of the Outdoor Fan

A detailed configuration of the outdoor fan 70 as the axial-flow fanaccording to the present embodiment is next described using FIGS. 3 to9. Here, FIG. 3 is a perspective view of the outdoor fan 70. FIG. 4 is aplan view of a positive pressure face side of the outdoor fan 70. FIG. 5is a plan view of a negative pressure face side of the outdoor fan 70.FIG. 6 is a side view of the outdoor fan 70. FIG. 7 is an enlarged viewof a joint 73 of the blade 72 and the vicinity thereof FIG. 8 is across-sectional view along I-I in FIG. 7. FIG. 9 is an enlarged view ofa front edge rib 76 and the vicinity thereof in FIG. 6. In thedescription below, an axial center (rotational center) of the outdoorfan 70 is indicated as axial center O, and the axis thereof is indicatedas rotational axis O-O.

The outdoor fan 70 is a propeller fan mainly with which a hub 71 and aplurality of (here, three) blades 72 are integrally resin-molded, asmentioned above, the plurality of blades 72 being formed so as toproject from an outer perimeter edge of the hub 71. The number of blades72 are not limited to three, and may be four or more, or the like.

The blade 72 has a blade shape that is forward advancing and forwardtilting (see FIGS. 4 and 5). The thickness of the blade 72 is greater atthe joint 73 with the hub 71, and becomes smaller going toward the outerperimeter side (see FIG. 9). An indented part 72 a formed on the rearedge of the blade 72 is disposed further toward the outer perimeter sidefrom the joint 73 (see FIGS. 3, 5, and 7). Here, a face on the sidewhere air flows in (upstream side in the direction of flow of air) whenthe outdoor fan 70 is rotated is indicated as a negative pressure face72 b, and a face on the opposite side (downstream side in the directionof flow of air) is indicated as a positive pressure face 72 c.

A first blade thinned-out part 74 is formed on the joint 73 of the blade72 so that a radial rib 75 extending radially toward the outer perimeterside is left. A front edge rib 76 continuing on a front edge of theblade 72 is formed in the joint 73 in a portion further toward the frontedge side of the blade 72 from the radial rib 75. A second bladethinned-out part 77 larger than the first blade thinned-out part 74 isformed between the front edge rib 76 and the radial rib 75 in thecircumferential direction.

Specifically, the blade thinned-out parts 74 and 77 are formed on thenegative pressure face 72 b of the blade 72. Instead of being formed onthe negative pressure face 72 b, the blade thinned-out parts 74 and 77may be formed only on the positive pressure face 72 c, or may be formedon both faces, being the negative pressure face 72 b and the positivepressure face 72 c.

The radial rib 75 has a thickness equal to that of the joint 73, and anend part in the axial direction thereof continues smoothly to the bladesurface of the blade 72 (see FIGS. 8 and 9). A plurality of (here, four)radial ribs 75 are disposed in an array in the circumferentialdirection. That is, a plurality of (here, four) first blade thinned-outparts 74 are disposed going from the rear edge side to the front edgeside of the blades 72 so as to be positioned on both sides in thecircumferential direction of the radial ribs 75. The second bladethinned-out part 77 is disposed on the front edge side in thecircumferential direction of the radial rib 75 disposed furthest on thefront edge side among the plurality of radial ribs 75. Therefore, theend parts in the axial direction of two adjacent radial ribs 75 holdinga first blade thinned-out part 74 between in the circumferentialdirection are smoothly continuous. The number of radial ribs is notlimited to four, and may be three or fewer or five or more.

The radial rib 75 extends on a straight line L extending radially towardthe outer perimeter side from the axial center 0 of the hub 71 whenviewing the hub 71 and the blade 72 from the axial direction (see FIG.7). The radial ribs 75 also are equidistantly disposed in thecircumferential direction. That is, all of the first blade thinned-outparts 74 have the same measurement in the circumferential directionregardless of the position in the radial direction, whereby the radialribs 75 are equidistantly disposed in the circumferential direction.

The spacing in the circumferential direction between the second bladethinned-out part 77 and the first blade thinned-out part 74 is largerthan the spacing in the circumferential direction between first bladethinned-out parts 74 (see FIGS. 5 and 7). That is, the second bladethinned-out part 77 has a larger measurement in the circumferentialdirection at the same position in the radial direction than the firstblade thinned-out part 74.

The front edge rib 76 is formed so as to project in the axial directionfrom the blade surface of the blade 72 on the front edge of the joint73, for the purpose of improving strength at the front edge of the blade72. The front edge rib 76 here has a roughly triangular pyramidal shape,and is formed on both sides, being the negative pressure face 72 b andthe positive pressure face 72 c, of the blade 72. A width in thecircumferential direction of the front edge rib 76 is larger than awidth in the circumferential direction of the radial rib 75 at the sameposition in the radial direction (see FIGS. 5 and 7). A depression 76 athat is roughly triangular when viewing the hub 71 and the blade 72 fromthe axial direction is formed on a portion toward the hub 71 of thefront edge rib 76. The front edge rib 76 may be formed only on thenegative pressure face 72 b or the positive pressure face 72 c, insteadof being formed on both the negative pressure face 72 b and the positivepressure face 72 c.

A rear edge rib 78 projecting in the axial direction from the bladesurface of the blade 72 is formed on a portion further toward the rearedge side from the first blade thinned-out part 74 of the joint 73. Therear edge rib 78 is formed on the negative pressure face 72 b and thepositive pressure face 72 c of the blade 72. That is, the first bladethinned-out part 74 and the radial rib 75 are formed on a portion towardthe front edge of the joint 73, and are not formed on a portion towardthe rear edge. The first blade thinned-out part 74 is positioned furthertoward the front edge of the blade 72 than the indented part 72 a whenviewing the hub 71 and the blade 72 from the axial direction (see thestraight line M extending to the outer perimeter side from the firstblade thinned-out part 74 disposed farthest toward the rear edge in FIG.7).

(3) Formation of the Outdoor Fan

A process for molding the outdoor fan 70 as the axial-flow fan accordingto the present embodiment is next described using FIGS. 10 and 11. Here,FIG. 10 is a cross-sectional side view of a mold 90 for describing aprocess for molding the outdoor fan 70. FIG. 11 is a cross-sectionalview illustrating a portion of the mold 90 for forming the joint 73 ofthe blade 72 and the vicinity thereof, for describing the process formolding the outdoor fan 70.

An injection-molding apparatus (not illustrated) having a mold 90 isfirst prepared. The mold 90 has a first mold 91 and a second mold 92that is movable with respect to the first mold 91. A cavity 93 forconfiguring the shape of the outdoor fan 70 is formed by combining thefirst mold 91 and the second mold 92 (see FIG. 10).

Resin is next injected from a hot water port 94 provided on the firstmold 91. The hot water port 94 is provided so as to inject resin intothe cavity 93 from a position near the axial center O of the cavity 93(here, a portion for forming the hub 71 of the outdoor fan 70). Theresin thus flows from the inner perimeter portion of the cavity 93 tothe outer perimeter side and travels throughout the cavity 93. At thistime, the resin flows in to the outer perimeter side passing throughportions, and the like, within the cavity 93 for forming the bladethinned-out parts 74 and 77, the radial rib 75, and the front edge rib76.

The mold 90 is next cooled with cold water, or the like, and the resinis hardened.

The mold 90 is next opened by undoing the combination of the first mold91 and second mold 92. The molded outdoor fan 70 is removed from themold 90.

(4) Features of the Outdoor Fan

The outdoor fan 70 as the axial-flow fan of the present embodiment hasfeatures such as the following.

First, in the outdoor fan 70 of the present embodiment, a first bladethinned-out part 74 is formed in the joint 73 of the blade 72 with thehub 71 so that the radial rib 75 extending radially toward the outerperimeter side is left, as mentioned above. Here, the radial rib 75extends on a straight line L extending radially toward the outerperimeter side from an axial center O of the hub when viewing the hub 71and the blade 72 from an axial direction (see FIGS. 5 and 7).

This radial rib 75 was discovered as a result of the present inventorshaving studied a rib shape when forming a thinned-out part on the joint73 of the blade 72, considering an inflow of resin during molding to aportion further toward an outer perimeter side from the thinned-outpart.

Such radial rib 75 accelerates the flow toward the outer perimeter sideof resin injected in the mold 90 during molding, and therefore allows afavorable inflow of resin to the portion further toward the outerperimeter side from the first blade thinned-out part 74 during molding.The radial rib 74 also allows resin injected into the mold duringmolding to flow more easily toward the outer perimeter side, compared tothe case when a rib not extending radially is left. In particular, here,because the radial rib 75 is configured to extend on a straight line L,the resin injected into the mold 90 during molding can be controlled toflow directly toward the outer perimeter side, and the resin flows moreeasily toward the outer perimeter side (see FIG. 11).

The thinned-out part can thereby be formed in the joint 73 of the blade72 while minimizing molding failure in the outer perimeter portion ofthe blade 72 in the outdoor fan 70 of the present embodiment.

In the outdoor fan 70 of the present embodiment, a plurality of (here,four) radial ribs 75 are disposed in a circumferential direction asmentioned above (see FIGS. 5 and 7).

Therefore, the portion where the resin flows to the portion furthertoward the outer perimeter side from the first blade thinned-out part 74can be increased in the circumferential direction during molding (seeFIG. 11).

The flow toward the outer perimeter side of resin injected into the mold90 during molding can thereby be further accelerated in the outdoor fan70 of the present embodiment. The resin also can be allowed to flow inuniformly to any position in the circumferential direction of theportion further toward the outer perimeter side from the first bladethinned-out part 74 during molding.

In the outdoor fan 70 of the present embodiment, a front edge rib 76continuing on a front edge of the blade 72 is formed in the joint 73 ona portion further toward a front edge side of the blade 72 from theradial rib 75 as described above. A second blade thinned-out part 77larger than the first blade thinned-out part 74 is formed between thefront edge rib 76 and the radial rib 75 in the circumferential direction(see FIGS. 5 and 7).

Here, the front edge rib 76 is formed in order to increase strength atthe front edge of the blade 72 as mentioned above, and a width in thecircumferential direction is larger than the radial rib 75 (see FIGS. 5and 7). Therefore, there is a possibility that the front edge rib 76 andthe vicinity thereof might be less likely to be cooled during molding.

In the outdoor fan 70 of the present embodiment, a second bladethinned-out part 77 larger than the first blade thinned-out part 74 isformed between the front edge rib 76 and the radial rib 75 in thecircumferential direction as mentioned above. Therefore, a situation inwhich the front edge rib 76 and the vicinity thereof are less likely tobe cooled can be minimized.

The occurrence of sink, marks during molding can thereby be minimizeddespite the fact that the front edge rib 75 is formed in addition to theradial rib 75 in the outdoor fan 70 of the present embodiment.

In the outdoor fan 70 of the present embodiment, the radial ribs 75 areequidistantly disposed in the circumferential direction (see FIGS. 5 and7).

Therefore, the resin easily flows in uniformly over the plurality of(here, four) radial ribs 75 during molding (see FIG. 11).

The resin can thereby be allowed to easily flow in more uniformly in thecircumferential direction to the portion further toward the outerperimeter side from the first blade thinned-out part 74 during moldingin the outdoor fan 70 of the present embodiment.

In the outdoor fan 70 of the present embodiment, an indented part 72 agoing in toward the front edge side of the blade 72 is formed on a rearedge of the blade 72. The first blade thinned-out part 74 is positionedfurther toward the front edge side of the blade 72 from the indentedpart 72 a when viewing the hub 71 and the blade 72 from an axialdirection (see FIG. 7).

Here, the indented part 72 a is formed in order to design forimprovement of ventilating performance and/or suppression of noise asmentioned above, and resin does not readily flow in to the indented part72 a and the vicinity thereof. Therefore, there is a possibility thatmolding failure in the indented part 72 a and the vicinity thereof mayoccur during molding.

As opposed to this, in the outdoor fan 70 of the present embodiment, thefirst blade thinned-out part 74 is positioned further toward the frontedge side of the blade 72 from the indented part 72 a as mentionedabove. Therefore, the resin flows in as far as the indented part 72 aand the vicinity thereof without passing the first blade thinned-outpart 74 during molding.

The inflow of resin to the indented part 72 a and the vicinity thereofis thereby ensured and molding failure in the indented part 72 a and thevicinity thereof can be minimized, despite the fact that both the firstblade thinned-out part 74 and the indented part 72 a are formed in theoutdoor fan 70 of the present embodiment.

INDUSTRIAL APPLICABILITY

The present invention is applicable to an axial-flow fan with which ahub and a plurality of blades are integrally resin-molded, the bladesbeing formed so as to project from an outer perimeter edge of the hub.

REFERENCE SIGNS LIST

70 Axial-flow fan

71 Hub

72 Blade

72 a Indented part

73 Joint

74 First blade thinned-out part

75 Radial rib

76 Front edge rib

77 Second blade thinned-out part

CITATION LIST Patent Literature

<Patent Literature 1> Japanese Laid-open Patent Application No,2011-74817

1. An axial-flow fan comprising: a hub; and a plurality of bladesintegrally resin-molded to the hub at a plurality of jointstherebetween, the plurality of blades being formed so as to project froman outer perimeter edge of the hub, each joint having at least one firstblade thinned-out part formed therein so that at least one radial ribextending radially toward an outer perimeter side is formed.
 2. Theaxial-flow fan according to claim I, wherein the at least one rib ofeach joint includes a plurality of radial ribs disposed in acircumferential direction.
 3. The axial-flow fan according to claim 1,wherein each radial rib extends along a straight line extending radiallytoward the outer perimeter side from an axial center of the hub whenviewing the hub and the blade from an axial direction.
 4. The axial-flowfan according to claim 1, wherein each joint further includes a frontedge rib continuing on a front edge of the blade in a portion furthertoward a front edge side of the blade the at least one radial rib; and asecond blade thinned-out part formed circumferentially between the frontedge rib and the at least one radial rib, with the second bladethinned-out part being larger than the first blade thinned-out part. 5.The axial-flow fan according to claim 2, wherein the radial ribs of eachjoint are equidistantly disposed relative to each other in thecircumferential direction.
 6. The axial-flow fan according to claim 1,wherein each blade includes an indented part formed on a rear edge sidethereof, with the indented part indented toward a front edge side of theblade from the rear edge of the blade; and the first blade thinned-outpart is positioned further toward the front edge side of the blade thanthe indented part when viewing the hub and the blade from an axialdirection.
 7. The axial-flow fan according to claim 2, wherein eachradial rib extends along a straight line extending radially toward theouter perimeter side from an axial center of the hub when viewing thehub and the blade from an axial direction.
 8. The axial-flow fanaccording to claim 2, wherein each joint further includes a front edgerib continuing on a front edge of the blade in a portion further towarda front edge side of the blade the at least one radial rib, and a secondblade thinned-out part formed circumferentially between the front edgerib and the at least one radial rib, with the second blade thinned-outpart being larger than the first blade thinned-out part.
 9. Theaxial-flow fan according to claim 2, wherein each blade includes anindented part formed on a rear edge side thereof, with the indented partindented toward a front edge side of the blade from the rear edge of theblade; and the first blade thinned-out part is positioned further towardthe front edge side of the blade than the indented part when viewing thehub and the blade from an axial direction.
 10. The axial-flow fanaccording to claim 3, wherein each joint further includes a front edgerib continuing on a front edge of the blade in a portion further towarda front edge side of the blade the at least one radial rib, and a secondblade thinned-out part firmed circumferentially between the front edgerib and the at least one radial rib, with the second blade thinned-outpart being larger than the first blade thinned-out part.
 11. Theaxial-flow fan according to claim 3, wherein the radial ribs of eachjoint are equidistantly disposed relative to each other in thecircumferential direction.
 12. The axial-flow fan according to claim 3,wherein each blade includes an indented part formed on a rear edge sidethereof, with the indented part indented toward a front edge side of theblade from the rear edge of the blade; and the first blade thinned-outpart is positioned further toward the front edge side of the blade thanthe indented part when viewing the hub and the blade from the axialdirection.
 13. The axial-flow fan according to claim 4, wherein theradial ribs of each joint are equidistantly disposed relative to eachother in the circumferential direction.
 14. The axial-flow fan accordingto claim 4, wherein each blade includes an indented part formed on arear edge side thereof, with the indented part indented toward the frontedge side of the blade from the rear edge of the blade; and the firstblade thinned-out part is positioned further toward the front edge sideof the blade than the indented part when viewing the hub and the bladefrom an axial direction.
 15. The axial-flow fan according to claim 5,wherein each blade includes an indented part formed on a rear edge sidethereof, with the indented part indented toward a front edge side of theblade from the rear edge of the blade; and the first blade thinned-outpart is positioned further toward the front edge side of the blade thanthe indented part when viewing the hub and the blade from an axialdirection.